The embodiments described herein relate to ball screw assemblies and, more particularly, to ball recirculation path for ball screw assemblies.
Some vehicle power steering systems employ an electric motor that interacts with a ball screw assembly which converts rotary motion of the electric motor to linear motion. The ball screw assembly includes a ball recirculation tube that follows a path with an elliptical trajectory.
The above-described arrangement, while effective for functionality and noise reduction, has limitations in the areas of packaging and manufacturing. In particular, a large envelope is needed to fit around the ball recirculation tube that encloses the ball recirculation path. The large envelope limits the ball track pitch that is available to designers, thereby eliminating the possibility of smaller pitch designs due to potential interference between the ball recirculation path and adjacent ball tracks of a helical path through which the load carrying balls travel. Additionally, a complex geometry for the ball nut mating interface leads to complications with manufacturing process capability.